1. Field of the Invention
The present invention relates to a liquid-droplet jetting apparatus which jets a liquid droplet from a nozzle.
2. Description of the Related Art
In an ink-jet printer described in US Published Patent Application No. 2008/0088666 (corresponding to Japanese Patent Application Laid-open No. 2008-94040), a suction cap, which comes into contact with/separates from an ink-jet head and which faces nozzles of the ink-jet head, and a suction pump which is connected to the suction cap are provided. Then, the suction pump is driven so that a space, which is defined by the suction cap and the ink-jet head when the suction cap is in contact with the ink-jet head, is reduced in pressure, and thereby discharging thickened inks and air bubbles in the ink-jet head from the nozzles. The sucked inks and air bubbles are discharged into a waste liquid tank connected to the suction pump through a tube.
Here, when the suction pump is driven in the state that the suction cap is in contact with the ink-jet head, and the thickened inks and air in the ink-jet head are discharged in the above-described manner, the ink with a high viscosity does not easily flow through the tube. Thus, there is sometimes a case that the ink with a high viscosity does not flow into the waste liquid tank from the suction cap via the suction pump. Particularly, the ink easily remains in the tube which connects the suction pump and the waste liquid tank and which is positioned on a downstream side with respect to the suction pump. Then, the viscosity of the ink remained in the tube increases as a standing time during which no discharging operation is performed goes by. Thus, when the similar operation is next performed in order to discharge the thickened inks and air in the ink-jet head, there is sometimes a case that the thickened ink remained in the tube does not flow by a suction speed of the suction pump. As a result, there is a risk that an internal pressure in the above-described tube increases to cause the tube to be pulled out of the suction pump.